CLASSIFICATION OP STRTJCTUEAL STEELS.
SECTION XVIIIa.—Influence of the method of manufacture on the properties of steel.—The first problem in writing specifications for structural steel is the advisability of prescribing the method by which it shall be manufactured. Some engineers hold that the way in which a bar or plate is made is a matter entirely beyond their dominion. Logically, this position is impregnable, but it is not so practically, for although there is no essential difference in the results obtained from open-hearth and Bessemer steel in the testing machine, there is good testimony to show that the product of the converter is an inferior metal. The evidence against Bessemer steel is made up of scattered individual opinions, many made on insufficient evidence, but they are too numerous to be ignored, and are fortified by the statements of men whose words are weighed, and who are disinterested in their decisions. Thus A. E. Hunt, with long experience as chief of The Pittsburg Testing Laboratory, wrote as follows :* "Numerous cases have come under our observation of angles and plates which broke off short in punching, but although makers of Bessemer steel claim that this is just as likely to occur in open-hearth metal, we have as yet never seen an instance of failure of this kind in open-hearth steel/'
Mr. Hunt quotes (loc. cit.) from a paper by Wailes that "these . mysterious failures occur in steel of one class, viz., soft steel made by the Bessemer process/'
There is also the testimony of W. H. White, Director of Naval Construction, Eoyal Navy.f "With converter steel riveted samples have given less average strength, greater variations in strength, and
* The Inspection of Materials of Construction in the United States. Journal I. and 3. I, Vol. II, 1890, p. 316.
t Experiments with Basic Steel. Journal I. and S. I,, Vol. 1,1892, p. 35.